Solenoid



R, M. NARDONE SOLENOID` Filed sept '7' 1944 March 25, 1947.

2y Sheets-Sheet l INVENTOR. RouLeoMMfdO/z' 'ArrUR/VE March 25, 1947. R.M. NARDQNE 2,417,990

sonENoIn Filed sept. '-7, 1944 2 sheets-sheet 2 INVENTOR. RolueoMhfclol.

A TTRNEY Patented Mar. 25, i947 2,411,990 soLENom Romeo M. Nardone,Teaneck, N. J., assignor to Bendix Aviation Corporation, Teterboro, N.J., a corporation o! Delaware Application September 7, 1944, Serial No.553,069

My invention relates to electromagnetic apparatus, and more particularlyto the mechanical construction thereof.

Electromagnets of the solenoid type are used extensively ininstallations of a character involving associated parts whereinvibrational and other disturbances are set up, which disturbances, whencommunicated to the solenoid assembly, tend to cause corresponding, butquite objectionable vibration and sometimes equally objectionablereciprocatory movements of the solenoid plunger with the result that thesleeve, in which the plunger is mounted, becomes unduly worn within arelatively short period therebynecessitating replacement. f

One of theobjects of my invention is to provide a solenoid equipped withmeans for counteracting the aforementioned tendency and for controllingthe effect thereof upon the solenoid plunger whereby wear on the plungersleeve is maintained at a minimum.

Another object of my invention is tol provide a solenoid wherein theinter-relationship, method of assembly, and the operationI of thevarious components not only contribute to th construction of anextremely compact device but serve to preclude noise or chatteroccasioned by vibration.

A further object of my invention is to provide a solenoid of theforegoing described character which is equipped with a coil assemblycapable of being inserted within the solenoid casing as a unit therebypermitting the coil assembly to be tested before being encased and to beeasily replaced if desired.

An important object of my invention is to provide a solenoid of theforegoing described character which is simple in construction, durablein use, efficient in operation, economical in manufacture and relativelysilent when deenergized.

With the above and other objects in view, as

will hereinafter appear, the invention consists in the combination, andarrangement of parts hereinafter set forth and illustrated in theaccompanying drawings, from which the several features of the inventionand the advantages attained thereby will be readily understood by thoseskilled in the art.

Referring to the drawing wherein like reference characters designatelike parts throughout the several views,

Figure l is a side elevation of my solenoid construction illustrated inconjunction with a portion oi an engine starting device.

Figure 2 is a perspective view of my invention illustrated inassociation with the brush actu 2 claims. (ci. 11s-341) 2 ating ring ofthe motor of the aforementioned device.

Figure 3 is-a perspective" view of my invention looking towards theplunger projecting end thereof.

Figure 4 is a sectional view taken on the line 1 4 `of the Figure 2.

Figure 5 is a disassembled perspective view of the coil assembly andcasing units, the latter unit being broken away to illustrate the fixedpole-piece therein.

Figure 6 is a disassembled perspective view of the plunger andinterlocking pin.

Figure 7 is-a sectional view taken on the line 'I--1 of Figure 4.

In practicing my invention, as illustrated in the drawings, I provide acasing unit I0 comprising cylindrical metallic shell or casing I I hav-ving an. open end and provided with radially disposed ilanges I2 adjacentsaid open end. The opposite end of the casingvis integrally formed withan end wall I3 provided with a central aperture in which is disposed ashank Il formed on the radial end face oi' a xed pole-piece or magneticplug I5 disposed axially within the casing. 'Ihe shank I4 is formed onits outer end with a circumferential lip IB coacting with the radial endface to secure the plug to the end wall I3 and in iixed relationtherewith. The circumferential face of the casing, adjacent the marginof the end wall I3, .is provided with a hole I'I, the purpose of whichwill hereinafter be mor fully described.

A coil assembly unit 20 is arranged within the casing and isintroducible therein as a unit, and which comprises a closure plate 2ltransversing the open end of the casing and provided with flanges 22engaging ilanges I2 and formed with a centrally disposed opening 23 andan outwardly 4disposed rib 24 surrounding the opening, the

latter having ilxed therein one end of a nonmagnetic guide sleeve 25 onwhich is mounted an exciting coil 26. The opposite end of the sleeve 25is provided with a collar 21 coacting with the plate 2l to maintainthe'coil 28 therebetween, said collar being connected to one lead wire28 of the coil 26 and engaging the casing I0 to establish a groundconnection between the coil and casing. The other lead wire 29 of thecoil is insulated and extends through a notch 30 formed in the peripheryof the collar and out of the casing through the hole I1 as depicted in25 tightly embraces the nlug I5 and forms a seal f therewith to precludethe escape of air therebetween from within the sleeve for a purposehereinafter made apparent. By thus disposing the plug within the sleeve,the plug serves to maintain centralization of the unit 20 within thecasing. An interlocking element or pin 3l is disposed in parallelrelation with the sleeve and extends axially through the rib 24 andplate 2| and the adjacent end face of the sleeve 25 for securing thesleeve to the plate against relative rotation, a side portion 32 of thepin projects and extends longitudinally within the bore of the sleeve25.

A movable pole-piece or magnetic plunger 35 is slidably mounted withinthe sleeve and has its circumferential face formed with a longitudinalgroove 36 receiving the portion 32 of the pin 3| whereby rotation of theplunger relative to the sleeve 25 is precluded. The confronting faces ofthe plunger 35 and plug l5 are formed with aligned sockets 31 receivingtherein opposite ends oi a coil spring 38 which functions to urge theplunger away from the plug when the solenoid is deenergized therebyestablishing an air chamber 39 between the plunger and plug as clearlyillustrated in Figure 4 of the drawings. Obviously, when the solenoid isenergized, the plunger is actuated in a direction towards the plug andthe air contained between the 'plunger and plug is forced outwardlytherefrom about and between the sleeve 25 and plunger 35, it being bornein mind that the plug l and sleeve 25 are tightly fitted to form a sealtherebetween. The opposite end face of the plunger is formed with adiametrically reduced projecting end section 40.

The plunger 35 is of a suitable diameter to establish a relatively closet with the sleeve 25 for decelerating the escape'of air, about andbetween the sleeve and plunger, from the chamber thereby counteractingvibratory reciprocation of the plunger when the solenoid is deenergizedwith It is obvious that the invention is not confined to the hereindescribed use therefor as it may be `itilized for any purpose to whichit is adaptable. It is therefore to be understobd that the invention isnot limited to the specific construction as illustrated and described asthe same is only illustrative of the principles of operation, which arecapable of extended application in various forms, and that the inventioncomprehends all construction within the scope of the appended claims.

What is claimed is:

l. In a solenoid construction, a hollow casing open at one end andclosed at the other by an end wall; `a plug of magnetic material axiallydisposed within said casing and having one end secured to said end wall;a. unitary coil assembly disposed within said casing, including aclosure plate at the open end of said casing, said plate having acentral opening in axial alignment with said plus; a sleeve ofnon-magnetic material axially disposed within said coil assembly, saidsleeve having one end projecting into the central opening and secured tosaid closure plate while its other end is removably mounted on the freeend of said plug to effect relative centralization, said plug and sleevebeing formed relatively to provide an air seal between the engagingportions; an energizing coil mounted on said sleeve; a collar fixed tothe inner end of said sleeve and coacting with said closure plate tomaintain said coil therebetween against axial displacement, said collarthe result that wear on the sleeve by the plunger Y is minimized.

The flanges I2 and 22 are provided with registering openings 4l for thereception of screws i not shown) whereby the solenoid may be secured toanother device with which it may be operatively associated, for example,a starter of the character disclosed in my co-pending application,Serial No. 525,417, led March 7, 1944, of which this application is acontinuation-impart. When utilized in conjunction with said starter, theend section 40 of the plunger 35 extends through an opening formed inthe wall or partition member 92 of the casing section and on whichmember 52 there is mounted a brush ring Ill provided with a radiallyoutstanding lug IIB which is engaged by the end section 40 of theplunger 35, the operating relation of the ring I Il and solenoid beingfully disclosed in the aforementioned co-pending application.

From the foregoing, it will be apparent that my invention provides anextremely simple and compact solenoid capable of being easily tested andassembled due to the unique and novel construction and arrangement ofthe units and their various components,

Without further elaboration the foregoing will so fully explain theinvention that others may,

'by applying current knowledge, readily adapt the same for use undervarious conditions of service. Moreover, it is not indispensable thatall the features of the invention be used conjointly since they may beemployed advantageously in various combinations and sub-combinations.

\ engaging said casing to establish a ground connection between saidcoil and casing; a plunger of magnetic material slidably mounted in theother end of said sleeve/and movable towards said plug when saidassembly is rendered effective; and a spring interposed between saidplug and plunger for urging the latter away from said plug when saidassembly is rendered ineffective and to thus provide an air chambertherebetween, said plungdisposed within said casing, including aclosure.

plate at the open end of said casing, said plate having a centralopening in axial alignment with said plug; a sleeve of non-magneticmaterial axially disposed within said coil assembly, said sleeve havingone end projecting into the central opening and secured to said closureplate while its other end is removably mounted on the free end oi saidplug to effect relative centralization, said plug and sleeve beingformed relatively to provide an air seal between the engaging portions:an energizing coil mounted on said sleeve; a collar fixed to the innerend of said sleeve and coacting with said closure plate to maintain saidcoil therebetween against axial displacement, said collar engaging saidcasing to establish a ground connection between said coil and casing; aplunger of magnetic material slidably mounted in the other end of saidsleeve and movable toward said plug when said assembly is renderedeiective; and a spring interposed between said said plug when saidassembly is rendered ineiiec- 5 6 tive and to thus provide an airchamber therebetween; interengaging means on said closure REFERENCESCITED Plate and plunger t0 restrict the latter for move The followingreferences are of record in the ment in an axial direction, said plungerand me of this patent; sleeve being formed relatively of such diameters5 as to decelerate the flow of air therebetween for UNITED STATESPATENTS cushioning vbratory reciprocations of said Number Name Dateplunger when said coil assembly is rendered nef- 2,343,806 Scofield Mar.7, 1944 fective. 2,353,835 Lane July 18, 1944 ROM'EO M. NARDONE. 102,361,826 Dowden Oct. 31, 1944

